Starting device for electromotors.



K. VON-BERGER STARTING DEVICE FOR ELEGTROMOTORS,

' APPLICATION FILED MAY 23, 1908.

923, 157, Patented June 1,1909.

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KARL VON DREGER, OF BERLIN, GERMANY.

STARTING DEVICE FOR ELECTROMOTORS.

Application filed May 23, 1908.

Specification of Letters Patent.

Patented June 1, 1909.

Serial No. 434,458.

To all whom it may concern:

Be it known that I, KARL VON Dnnenn, a citizen of the Empire of Germany,residing at Berlin, in the Empire of Germany, have in vented a new anduseful Starting Device for Electromotors, of which the following is aspecification.

There are known starting devices for electromotors comprising a leverriding over the waved circumference of a segment or the like, whichlatter carries two contact springs and is elastically connected with theoperating handle by means of a spiral spring. For starting theelectromotor the operating handle is then turned in one direction andthe lever serves for braking the segment or the like, so as to preventit from following too rapidly the operating handle, so that the twocontact springs may successively pass over various contact piecesarranged in two concentric arcs, and for stopping the electromotor theoperatinghandle requires to be turned back to its initial position. Suchstarting devices present two serious defects. One defect is, that thetwo contact springs also lag behind the operating handle during theswitcliing-oif operation, which under circumstances may create seriousdisturbances. The other defect is, that the resistance offered to thelever by the waved circumference of the segment or the like does notdecrease in proportion to the diminishing tension of the strained spiralspring on the segment or the like with the two contact springs followingthe operating handle after the latter has been turned forward forstarting the electromotor.

My invention relates to improvements in such starting devices forelectromotors, whereby the said two defects are avoided.

Instead of the segment or the like I employ a ring loose on theperiphery of a drum which is elastically connected with the operatinghandle by means of a spiral spring and I provide the ring on its outsidewith waved surfaces and notches. A lever is provided which is adapted toride with its free end over the waved surfaces of the ring during theforward turn of the operating handle and to engage in the notches of thering for stopping same during the return of the operating handle.lvleans are provided for coupling the ring with the drum during theforward turn and for disconnecting the former from the latter during thereturn. The operating handle is adapted to at once take along with itduring its return the drum with the two contact levers. Thus the firstdefect named above is avoided. The waves in the waved surfaces of thering are made irregular in such a manner, that in each series of wavesthe first wave is made the shortest and highest and the last wave ismade the longest and lowest, while the intermediate waves successive ydecrease in height and increase in length. Then the braking effect ofthe lever upon the ring will decrease in bout the same proportion as thetension of the spiral spring diminishes. Thus the second defect namedabove is avoided.

I will now proceed to describe my invention with reference to theaccompanying drawing, in which Figure 1 is asection through a startingdevice on the line ccZ in Fig. 2, when looked at in the direction of thearrows, and Fig. 2 is another section through the same on the line al inFig. 1., when looked at in the direction of the arrows. Fig. 3 is a viewsimilar to Fig. 2, showing a slightly modified construction.

Similar characters of reference refer to similar parts in all the views.

In a casing or box 1 of any known construction a shaft 8 is provided,which may form a part of any known device not shown. This shaft 8extends through a cover 30 of the box 1 and carries without a looseoperating handle 23 and within a loose spring-d rum 6 and a loose lever20. The lever 20 is shown as provided with two claws 25 which engage incorresponding recesses in the nave of the operating handle 23. Therebythe lever 20 is obliged to partake in the movement of the operatinglever 23. On the periphery of the drum 6 a ring 9 is mounted to turn,while it is prevented from axially shifting by a collar 6 and aninternally screw-threaded ring 31 or the like. In the race of the ring 9there is provided a recess 11 (see Fig. 2) in the periphery of the drum6, and. in this recess 11 a pawl 10 is mounted to rock on a suitable pinshown, while a leaf spring 12 serves for pressing the pawl 10 on theinner circumference of the ring 9. The latter is provided with threenotches 13, into any of which the pawl 10 can engage. A. spiral spring19 is provided within the drum 6 and is attached with its internal endto the nave of the lever 20 and with its external end to the inside ofthe drum 6, as is shown. The rim of the drum 6 is provided with aprojection 24 on which the lever 20 normally rests under the action of aslight tension in the spring 19. The periphery of the ring 9 is providedwith three series of waves 17 and three notches 14, 14 14 which latterare set at an angle of 12 0 from one another. The first .wave in eachseries 17 (when counting from any of the notches 14", 14 14 in adirection opposite to that of the hands of a clock) is made the shortestand the highest, while the following waves successively decrease inheight and increase in length, as is clearly shown in Fig. 2. In thecasing 1 a pin 15 is provided, on which a lever 14 is mounted to rock.The hooked free end of this lever 14 is adapted to ride over the wavedperiphery of the ring 9. Between the lever 14 and the inside of thecasing 1 a helical spring 16 is inserted, which serves for pressing thehooked end of the lever 14 on the ring 9. The tension of the helicalspring 16 can be regulated by means of an adjusting screw 32 in thelever 14. On

the side of the drum 6 and insulated therefrom are fastened two contactsprings 4 and 5, which are electrically connected with one another.Sufficient play is left to the three parts 6, 20 and 23, which canlongitudinally shift on the shaft 8 and are normally pressed togetheragainst a collar 33 on the shaft 8 by the two contact springs 4 and 5.

On the inside of the casing 1 and insulated therefrom are fastened forexample a contact strip 2, six contact pieces 3, 3 and two insulatingpieces 27, all of which are disposed in two concentric rows around theshaft 8 and are well known. The contact spring 4 is adapted to slideover one insulating piece 27 and the contact strip 2, while the othercontact spring 5 is adapted to slide over the other insulating piece 27and the series of contact pieces 3, 3 and to strike against a projection28 of the last contact piece 3 whereby the turn of the drum 6 with thetwo contact springs 4 and 5 in the direction of the arrow 18 is limited.The angle through which the two contact springs 4 and 5 can be turnedfrom their normal position shown in full lines in Fig. 2 to their otherextreme position over the last contact piece 3 amounts to 120 like theangle between any two of the notches 14, 14 14 in the ring 9. Theoperating handle 23 normally occupies the same position as the twocontact springs 4 and 5, which position is indicated by the dottedcenter line A8, and can be turned beyond the last contact piece 3 to theother extreme position indicated by the dotted center line B*8. In thisextreme osition the operating handle 23 may be hell it bearing againstsome pin provided on the cover 30, or it may be secured by means of anyknown stopping, pinching or locking device.

The starting device operates as follows: For the normal position of theoperating handle 23 in the dotted center lineA8 in l by hand, r

Fig. 2 the hooked end of the lever 14 engages in any of the threenotches 14 (as shown), 14 14 and the pawl 10 engages in thecorresponding notch 13 of the ring 9. When the operator is desirous ofstarting the electromotor, he turns the operating handle 23 in thedirection of the arrow 18 to the other extreme position B8 with anyspeed he likes. Thereby of course the lever 20 is moved off from theprojection 24 of the drum 6 and the spiral spring 19 is strained, sothat its tension will pull the drum 6 with the two contact springs 4 and5 forward in the direction of the arrow 18, and the .pawl 10 will takethe ring 9 along with it, but the spring-pressed lever 14 will brake thering 9 and prevent it together with the drum 6 and the two contactsprings 4 and 5 from following too rapidly the operating lever 23.During this movement the tension of the spiral spring 19 will diminish,but as the waves 17 also decrease in height and increase in length, thediminishing tension of the spiral spring 19 will be still able toovercome the friction of the hooked end of the lever 14 on the peripheryof the ring 9 and to move the contact springs 4, 5 to their extremeposition in which one of them (5) strikes the projection 28 of the lastcontact piece 3 In this manner the two contact springs 4 and 5 are movedforward with a nearly uniform speed. The small tension still remainingin the spiral-spring 1-9 will suffice for pressing the contact spring 5against the projection 28 and thus securing the two contact s rings intheir extreme position, while the liboked end of the springpressed lever14 engages in the following notch 14 of the ring 9. Of course the lever20 will be at a small distance from the projection 24. In this mannerthe electromotor is gradually started in spite of any rapidity in themovement of the operating handle 23. When the operator wants to StQptl16*6l6Ct1O motor, he turns the operating handle 23 back from theposition B-8 to the initialposition A-S with any speed he likes. Thelever 20 striking the projection 24 will thereby take along with it thedrum 6 and the pawl 10 will slide on the inner circumference of the ring9 until it engages in the following notch 13. Thus the two contactsprings 4 and 5 are moved back as rapidly as the operating handle 23, asit should be. The ring 9 is of course prevented from returning by thehooked end of the lever 14 engaging its notch 14 The starting devicedescribed may be varied in many respects without departing from thespirit of my invention. For example the lever 14 may be weighted insteadof spring-pressed. The ring 9 may be provided on its side with a wavedgroove, as is indicated in Fig. 3, it having on its inside nearer theshaft 8 substantially the same outline as the waved periphery of thering 9 shown and described above with reference to Fig. 2. The free endof the lever M may have a pin or a pin with a roller for engaging in thewaved groove. In this case the lever 14 is preferably not spring-pressedor weighted but is pivotally connected with the rod 34 of a pistonfitting loosely in the cylinder 29 of an air-brake or liquid-brake of aknown construction, as is indicated in Fig. 3.

I claim:

1. In a starting device for electromotors. the combination with anoperating handle, of a drum, a spring connecting said operating handlewith said drum for pulling the latter forward, a ring turnable on saiddrum, means forconnecting said ring with said drum during the forwardturn of said operating handle for switching-on, means for stopping saidring during the return of said operating handle for switching-oil,contact pieces, two electrically connected contact springs on said drumand insulated therefrom and adapted to slide over said contact pieces,and means for braking said ring with a force decreasing in proportion tothe diminishing tension of said spring so as to move said two contactsprings with a nearly uniform speed, said operating handle being adaptedduring its re turn to take along with it said drum with said two contactsprings.

2. In a starting device for eleotromotors, the combination with anoperating handle, of a drum provided with a recess and a projection, aspring connecting said operating handle with said drum for pulling thelatter forward, a ring turnable on said drum and provided with a notch,a spring-pressed pawl in the recess of said drum and adapted to engagein the notch of said ring for taking the latter along with it during theforward turn of said operating handle for switching-on, means forstopping said ring during the return of said operating handle forswitchingoff, contact pieces, two electrically connected contact springson said drum and insulated therefrom and adapted to slide over saidcontact pieces, and means for braking said ring with a force decreasingin proportion to the diminishing tension of said spring so as to movesaid two contact springs with a nearly uniform speed, said operatinghandle being adapted during its return to strike the projection of saiddrum and thereby take along with it the latter with said two contactsprings.

3. In a starting device for electromotors, the combination with anoperating handle, of a drum provided with a recess and a projection, aspring connecting said operating handle with said drum for pulling thelatter forward, a ring turnable on said drum and provided on its innercircumference with a notch and on its outside with a waved surface and anotch, spring-pressed pawl in the recess of said drum and adapted toengage in the internal notch of said ring for taking the latter alongwith it during the forward turn of said operating handle forswitchingon, a support, a lever mounted on said sup port to roclr andadapted to ride with its free end over the waved surface of said. ringand to engage the external notch of same for preventing it fromreturning during switching-oif, contact pieces, two electricallyconnected contact springs on said drum and insulated therefrom andadapted to slide over said contact pieces, and means for braking saidring by means of said lever, the waves in the waved surface of said ringsuccessively decreasing in height and increasing in length for reducingthe fi 'ction of said lever in proportion to the diminishing tension ofsaid spring so as to move said two contact springs with a nearly uniformspeed, and said operating handle being adapted during its return tostrike the projection of said drum and thereby take along with it thelatter with said two contact springs.

4. In a starting device for electroinotors, the combination with aplate, of a shaft at right angles to said plate, an operating handle onsaid shaft, a drum loose on said shaft, a spring connecting saidoperating handle with said drum for pul ing the latter forward, a ringturnable on said drum, means for connecting said ring with said drumduring the forward turn of said operating handle for switching-on, meansfor stopping said ring during the return of said operating handle forswitching-oil, contact pieces on said plate, two electrically connectedcontact springs on said drum and insulated therefrom and adapted toslide over said contact pieces, and means for braking said ring with afo ce decreasing in proportion to the diminishing'tension of said springso as to move said two contact springs with a nearly uni- .form speed,said operating handle being adapted during its return to take along withit said drum with said two contact springs.

5. In a starting device for electromotors, the combination with a plate,of a shaft at right angles to said plate, an operating handle on saidshaft, drum loose on said shaft and provided with a recess and aprojection,

a spring connecting said operating handle with said drum for pulling thelatter forward, a ring turnable on said drum and provided with a notch,a spring-pressed pawl in the recess of said drum and adapted to engagein I the notch of said ring for taking the latteralong with it duringthe forward turn of said operating handle for switching-on, means forstopping said ring during the return of said operating handle forswitching-oil, contact pieces on said plate, two electrically connectedcontact springs on said drum and insulated therefrom and adapted toslide over said contact pieces, and means for braking said ring with aforce decreasing in proportion to the diminishing tension of said springso as to move said two contact springs with a nearly uniform speed, saidoperating handle being adapted during its return to strike theprojection of sale drum and thereby take along with it the latter withsaid two contact springs.

6. In a starting device for electromotors, the combination with a plate,of a shaft at ri ht angles to said plate, an operating handle on saidshaft, a drum loose on said shaft and provided with a recess and aprojection, a spring connecting said operating handle with said drum forpullin the latter forward,

5 a ring turnable on said drum and provided on its inner circumferencewith a notch and on its outside with a waved surface and a notch, aspring-pressed pawl in the recess of said drum and adapted to en age inthe internal notch of said ring for taking the latter along with itduring the forward turn of said operatinghandle for switching-on, alever mounted on said plate to rock and adapted to ride with its freeend over the waved surface of said ring and to engage the external notchof same for preventing it from returning during switching-off, contactpieces on said plate, two electrically connected contact springs on saiddrum and insulated therefrom and adapted to slide over said contactpieces, and means for braking said ring by means of said lever, thewaves in the waved surface of said ring successively decreasing inheight and increasing in length for reducing the friction of said leverin proportion to the diminishing tension of said spring so as to movesaid two contact springs with a nearly uniform speed, and said operatinghandle being adapted during its return to strike the projection of saiddrum and thereby take along with it the latter with said two contactsprings.

7. In a starting device for electromotors, the combination with a plate,of a shaft at right angles to said plate, an operating handle on saidshaft, a drum loose on said shaft, a spiral spring connecting saidoperating handle with said drum for pulling the latter forward, a ringturnable on said drum, means for connecting said ring with said drumduring the forward turn of said operating handle for switching-on, meansfor stopping said ring during the return of said operating handle forswitching-off, contact pieces on said plate, two electrically connectedcontact springs on said drum and insulated therefrom and adapted toslide over said contact pieces, and means for braking said ring with aforce decreasing in proportion to the diminishing tension of said spiralspring so as to move said two contact springs with a nearly uniformspeed, said operating handle being adapted during its return to takealong with it said drum with said two contact springs.

8. In a starting device for electromotors, the combination with a plate,of a shaft at right angles to said plate, an operating handle on saidshaft, a drum loose on said shaft and provided with a recess and aprojection,

a spiral spring connecting said operating handle with said drum forpulling the latter forward, a ring turnable on said drum and providedwith a notch, a spring-pressed pawl in the recess of said drum andadapted to engage in the notch of said ring for taking the latter alongwith it during the forward turn of said operating handle forswitching-on, means for stopping said ring during the return of saidoperating handle for switchingoff, contact pieces on said plate, twoelectrically connected contact springs on said drum and insulatedtherefrom and adapted to slide over said contact pieces, and means forbraking said ring with a force decreasing in proportion to thediminishing tension of said spiral spring so as to move said two contactsprings with a nearly uniform speed, said operating handle being adaptedduring its return to strike the projection of said drum and thereby takealong with it the latter with said two contact springs.

9. In a starting device for electromotors, the combination with a plate,of a shaft at right angles to said plate, an operating handle on saidshaft, a drum loose on said shaft and provided with a recess and aprojection, a spiral spring connecting said operating handle with saiddrum for pulling the latter forward, a ring turnable on said drum andprovided on its inner circumference with a notch and on its outside witha waved surface and a notch, a spring-pressed pawl in the recess of saiddrum and adapted to engage in the internal notch of said ring for takingthe latter along with it during the forward turn of said operatinghandle for switching-011, a lever mounted on said plate to rock andadapted to ride with its free end over the waved surface of said ringand to engage the external notch of same for preventing it fromreturning during switchingoff, contact pieces on said plate, twoelectrically connected contact springs on said drum and insulatedtherefrom and adapted to slide over said contact pieces, and means forbraking said ring by means of said lever, the waves in the waved surfaceof said ring successively decreasing in height and increasing in lengthfor reducing the friction of said lever in proportion to the diminishingtension of said spiral spring so as to move said two contact springswith a nearly uniform speed, and said operating handle being adaptedduring its return to strike the projection of said drum and thereby takealong with it the latter with said two contact springs.

KARL VON DREGER.

Witnesses NOLDEMAR HAUPT, HENRY Hasrnn.

